Trident, Britain’s nuclear weapons system, divides opinion. That was apparent this week when the Government published the results of a two-year, detailed study of the alternatives.

Some people say Britain should surrender our nuclear weapons tomorrow, regardless of what threats we face. While others seem to believe it’s unpatriotic to even consider anything other than the full-scale Trident system we built for the Cold War threats of yesterday and defense for the future.

Personally, I think the world has changed. I am not, and never have been, a believer in unilateral disarmament. But I do share President Obama’s belief that the world’s nuclear powers can and must work together to move on from the Cold War arms race and reduce our nuclear arsenals. It’s how to make the world safer.

That’s why when we formed the coalition we made clear we wanted this full, in depth analysis of the alternatives to Trident. It’s a very technical, neutral, official study that has simply showed for the first time there are other options.

The report shows that we can retain a nuclear deterrent without having the Cold War, super-charged system of the past: armed to a hair trigger every second of every day, able to flatten Moscow at the push of a button.

Of course, keeping Trident, unchanged in even the tiniest detail, has been an article of faith for the leadership of the Conservative and Labour parties for so long that this report is the first time civil servants have ever been asked to look at alternatives. In fact, in pursuit of his “legacy”, Tony Blair forced through the renewal of Trident, back in 2006, without even asking the question of whether it was the best way to protect us from the threats of today.

As Shirley Williams’ excellent article on Lib Dem Voice set out this week, it’s only because there are Liberal Democrats in Government that this essential question has now been answered. We have broken the conspiracy of silence that has dogged rational decision-making for too long.

In the light of the Trident Alternatives Review, we’ll be debating our party’s position on nuclear defence at this autumn’s Conference. Some people will attack us for proposing an alternative to Trident, saying we can’t predict the future so we need every last bolt and screw of this multi-billion pound weapons system “just in case.”

But we need to protect ourselves from the threats of the future not the past. We haven’t kept a fleet of dreadnoughts in case the Germans invade across the North Sea. We don’t have a standing army on the cliffs of Dover to protect us from the French – though maybe I shouldn’t give UKIP any ideas!

The truth is today we don’t face the old Cold War threats: we face new ones – stateless groups, terrorists groups, failed and rogue states. The Trident system isn’t designed for those threats, but for different ones, so it’s time to move on.